Various communication networks comprise multiple Base Transmission Station (BTS) sites that transmit and receive Radio Frequency (RF) signals to and from mobile devices using one or more antennas. In various network configurations, the BTS sites communicate the RF signals with other elements in the network in a sampled and digitized form. For example, the Common Public Radio Interface (CPRI) standard defines interfaces between Radio Equipment Controllers (REC) and local or remote Radio Equipment (RE) units of the BTS sites. The CPRI specifications are described, for example, in “Common Public Radio Interface (CPRI); Interface Specification,” version 6.1, Jul. 1, 2014, whose disclosure is incorporated herein by reference.
In various applications, CPRI signals are transmitted as 10-bit symbols using an encoding scheme that maps 8-bit characters to the 10-bit symbols (referred to as 8b/10b encoding). An 8b/10b line coding scheme is defined, for example, in IEEE Standard 802.3-2005, entitled “IEEE Std 802.3-2005: Part 3: Carrier sense multiple access with collision detection (CSMA/CD) access method and physical layer specifications,” Dec. 12, 2005, whose disclosure is incorporated herein by reference.
Some high rate CPRI signals use a 64b/66b line coding scheme in which 64-bit blocks (i.e., eight 8-bit characters) are mapped into 66-bit line codes. A 64/66b line coding scheme is defined, for example, in clause 49 of the IEEE standard 802.3-2008, entitled “Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements Part 3: Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications,” Dec. 26, 2008, whose disclosure is incorporated herein by reference.
CPRI signals may be sent over various types of networks, such as, for example, optical networks. Several schemes for sending CPRI signals over the Optical Transport Network (OTN) are described, for example, in ITU-T G-series Recommendations—Supplement 56, entitled “OTN Transport of CPRI signals, Series G: Transmission Systems and Media, Digital Systems and Networks,” July, 2015, whose disclosure is incorporated herein by reference.